Electric oven



'June 5, 1928. 1,672,724

F. H. MCCORMICK amcmc cvmz I Filed Oct. 18, 1926 Inventor: Francis H.McCor-mLck,

His Att Pneg,

Patented June 5, 1928.

UNITED STATES.

Inningsis:ntecomucnr,"or onnnntilyn. nlnmors, ASSIGNOB TO EDISON unscrew urnuncn county, or cmcaoo, rumors, A CORPORATION or new ELEC'IBIG OVEN.

Application filed October is, 1826. Serial in. 142,253.

My invention relates to electricovens and;- has .for its object the .provision otsimple,; reliable and efficient heating means for the" f r portioned that when connected in parallel. 6' More specifically, my invention-relates -to an improved organization and "arrangement,

oven.-

of the heating units in an: electric oven whereby the controlof the; oven is greatly simplified. It has heretoforebeen custom l0 ary in the construction of electric ovens to provide a heating unit in the top of the oven and another heating unit in the tom of. the oven, these units being 'each by 'meansof a suitable switch whereby the series or in parallel to give difierent rates .of heat generation.-.

In-carrying outmy invention, I provide heatingunits in the top and bottom of the oven which are arranged to be controlled from a single; switch and yet avoid the limitation heretofore characteristic of single switch control. In one embodiment of my tially more heat than ,the unit in the bottom of the oven and connect the two units to a three heat switch. whereby they are c0nnected in parallel to give a rapid rate of heating when the oven is being preheated, the bottom unit is operated a one for the usual high tem rature baking and roastin operations, an the two units are connecte in series for lower temperature cooking operations. v

For a more complete understanding of my invention reference should be had to the accompanying drawing in which Fig. 1 is a diagrammatic .view of'an electric oven em ying my invention, while Figs. 2, 3 and 4 are diagrams showin the various electrical connections for the eating units. Referring to the drawing, I have shown my invention in one form as applied to an oven 10 of any well known form, such, forexample, as provided on electric ranges for boiling and baking. Inone embodiment of my invention I provide two electric heating units in the oven, a heating unit 11 in the top of the oven, and a heating unit 12 in the bottom. These heating units are both of the well known resistor type consisting of a resistance heating conductor made of 5; suitable metal, such as a nickel-chromium intense heat from the upper unit used .forb'roihng meats, etc. be of such size as to maintain the usual be.

f divided into sections. which are controlled .1

invention I provide. a heating unit in the top ofthe oven which dissipates substan h alloy, The upper heating unit 11 18 higher wattage, or dissipates more the lower unit. .The two ,units toa suitableelectrical suppiy source a rapid rate of heating will be obtained, where by the oven may be heated quickly, or the alone The lower unit will ing temperature of approximately $00 when connected alone to the supply so and the two units will further be so portioned that when they are coimectedic. series across the supply source the oven will to "be maintained at a suitable temperature low temperature baking and for boiling op- I erations. Asingle three-heat switch 14 of any, suitable construction is provided for controlling'the connections of the two heat- 1ting units in the manner indicated. The

electrical connections of V the two heating units, as previously described, are shown in Figs. 2, 3 and 4 for the high,-medium low heats respectively.

The sizes of the heatingunits will, course, vary with the size and character of the oven. For an oven' requiring 2000 watts energy input for quick heating, 1 have found that very satisfactory results may be 88 obtained with an upper heating unit of 1400 watts capacity and a lower heating unit of 600 watts capacity. It will be observed that with these two units connected in parallel, as shown in Fig. 2, the energy input no will be 2000 watts for quick heating. With the lower heating unit connected alone, indicated in Fig. 3, the input will be 600 watts which in the oven under consideration maintained a very satisfactory baking temer; perature. When the two units are connected in series, as indicated in Fig. 4, the en ergy input will be 420 watts total, 295 watts being taken by the lower unit and 125 by the upper unit, which gives a very satisfactory temperature and heat distribution for lower temperature baking and boiling.

should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those sln'lled in the art without departin from the spirit of my invention, the scope 0 which is set forth in the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination with an oven of electric heating means therefor comprising heating units in the top and bottom of saidoven, one of said heating units being arranged to maintain a desired baking temperature and the other heating unit having at least twice the heat capacity of the first, an electrical supply source for said heating units, and means for connecting both of said heating units to said supply source for preheating the oven and for connecting the first heating unit alone for normal operation.

2. The combination with an oven of electric heating means therefor comprising a heating unit in the bottom of the oven adapted to maintain a desired baking tempera ture, a heating unit of high heat capacity in the top of the oven, an electrical supply source, and means for connecting both of said heating units to said supply source for preheating the oven, for connecting said bottom heating unit alone for normal operation, and for connecting both of said heating 4 units in series for operation at a lower temperature.

3. The combination with an oven, of electric heating means therefor comprising a heating unit in the bottom of the oven arranged to maintain a desired baking temperature, and a heating unit in the top of the oven arranged to supply a relatively large amount of heat when connected in parallel with the lower unit, whereby the oven may be heated rapidly, and to maintain a desired lower operating temperature when connected in series with said bottom unit.

4. The combination in an electric oven,,of a heating unit in the bottom of the oven arranged to maintain a desired cooking temperature after the oven has been heated to that temperature, a heating unit in the top of the oven of relatively large heat capacity, an electric supply source, and switching means for connecting said units in parallel to said supply source whereby the oven is heated rapidly to a desired temperature, for disconnecting the upper unit whereby the temperature is maintained by the lower unit only, and for connecti said units in series to maintain a lower coo ing temperature.

5. The combination in an electric oven, of a heating unit in the bottom of said oven arranged to maintain a desired baking temperature, a heating unit in the top of the oven arranged to supply a relatively large amount of heat, an electrical supply source, and a single switch' means for controlling the connections of said units to said source, whereby the two units may be connected in parallel for preheating the oven, the bottom eating unit connected alone for high temperature cooking operations, and the two units connected in series for low temperature cooking operations.

In witness whereof, I have hereunto set my hand this lath day of October, 1926.

FRANCIS H. MOCORMICK. 

